1. Field of the Invention
The present invention relates to a cleaning apparatus, and more particularly, to a cleaning apparatus including a feeding device for holding and moving a workpiece.
2. Description of the Related Art
A high-pressure cleaning machine is used for cleaning of products, particularly mechanical parts such as automobile parts. The high-pressure cleaning machine directs onto an object to be cleaned (hereinafter referred to as the “workpiece”) high-pressure jets obtained by pressurizing cleaning liquid to a high pressure and jetting it from nozzles. At this time, cutting oil, chips or other foreign matters, or burrs on a work surface are removed by an impact force and cleavage force generated when the high-pressure jets impinge on the work surface. Because the jets change their orientation upon contact with the work surface to flow along the work surface, the high-pressure cleaning machine is suitable for cleaning and deburring of mechanical parts having outer surfaces with complicated shapes (for example, Japanese Published Unexamined Patent Application No. 2004-141811 (claim 1, FIGS. 1 to 6) and U.S. Pat. No. 8,034,191 (FIGS. 9 to 15)).
The cleaning apparatus disclosed in the Japanese Published Unexamined Patent Application No. 2004-141811 performs cleaning by sequentially positioning while moving nozzles so that the nozzles face a single workpiece hole. The cleaning apparatus disclosed in the U.S. Pat. No. 8,034,191 performs cleaning by controlling the attitude of the workpiece while holding the workpiece with a multi-joint robot so that the workpiece is directed toward nozzles.
However, in the cleaning apparatus disclosed in the Japanese Published Unexamined Patent Application No. 2004-141811, there is a problem in that it takes a long time for cleaning because cleaning is performed by sequentially moving and positioning the nozzles so that the nozzles face a single workpiece hole. There is also a problem in that, when numerous holes to be cleaned are arranged or a wide surface is cleaned, the moving time of the nozzles becomes excessive, leading to deterioration in productivity because the range to be cleaned at a time is narrow.
In addition, there is also a problem in that, when the nozzles are moved in the same manner as the cleaning apparatus disclosed in the Japanese Published Unexamined Patent Application No. 2004-141811, the construction for ensuring the sealing performance is complicated in the case of supplying an ultrahigh-pressure cleaning liquid to the nozzles.
On the other hand, in the cleaning apparatus disclosed in the U.S. Pat. No. 8,034,191, there is a problem in that complex control is necessary to linearize the movement locus of the workpiece because the workpiece is held by the multi-joint robot and directed toward the nozzles by rotary motion. In the case of cleaning or deburring with high-pressure jets, the high-pressure jets need to strike the workpiece exactly along its outline. With the multi-joint robot, it is difficult to obtain high positioning accuracy, repeatability, or locus accuracy, and therefore a high cleaning or deburring effect is hard to obtain.
Furthermore, the multi-joint robot is directly splashed with the high-pressure water jetted from the nozzles or indirectly splashed with the high-pressure water bounced off the workpiece. Because the multi-joint robot is a precision component, unfortunately, it is likely to be damaged due to contact with high-pressure water.